CANBERRA(XINHUA) - Australia's Northern Territory (NT) has introduced coronavirus restrictions after reporting its first locally-acquired case.

Mr Michael Gunner, the chief minister of the state, announced on Thursday (Nov 4) that an unvaccinated man in his 20s was diagnosed with the virus in Katherine, about 300km south of the capital Darwin.

He said the man has not travelled outside the state recently. "We don't know where and we don't know when but this is community transmission," Mr Gunner told reporters.

"He has caught it from someone in the territory but we don't know who."

It is the first confirmed case of community transmission in the state since the start of the pandemic.

Mr Gunner said the man was likely infectious in the Katherine and Darwin communities from Sunday until Tuesday.

As a result, Katherine has been plunged into a 72-hour lockdown that started at midnight Friday.

Under the lockdown, Katherine residents are only allowed to leave home for medical treatment, shopping for essential goods, performing essential work, exercising or providing care.

Darwin residents who are fully vaccinated against Covid-19 are required to wear masks outdoors but can otherwise go about life as normal, while those who are not inoculated are subject to full lockdown restrictions.

Anyone caught breaching the restrictions will receive a A$5,000 (S$4,994) fine.

As of Wednesday, 77.8 per cent of people in the territory aged 16 and over had received one vaccine dose and 64.7 per cent were fully inoculated.

"This is another reminder that the territory is absolutely vulnerable to Covid-19," Mr Gunner said.

"But you are more likely to catch Covid if you are unvaccinated, and you are way, way more likely to get seriously ill from Covid if you are unvaccinated."

Victoria, New South Wales and the Australian Capital Territory on Friday reported a total of 1,598 new locally-acquired coronavirus infections and 13 deaths.